{"id":"CVE-2026-68155","summary":"libceph: Reject monmaps advertising zero monitors","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Reject monmaps advertising zero monitors\n\nA message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a\nmonitor to the client. This monmap contains information about the\nexisting monitors in the cluster. Currently, a monmap indicating that\nthere are zero monitors in the cluster is treated as valid. However, it\nis impossible to have zero monitors in the cluster and still receive a\nvalid monmap from a monitor. Therefore, such a monmap must be corrupted\nand should be treated as invalid. Furthermore, a monmap with a monitor\ncount of zero can subsequently crash the client when attempting to open\na session with a monitor in __open_session(). This happens because the\n\"BUG_ON(monc-\u003emonmap-\u003enum_mon \u003c 1)\" assertion in pick_new_mon() is\ntriggered.\n\nThis patch extends a check in ceph_monmap_decode() to also reject\narriving mon_maps with num_mon == 0 rather than only with\nnum_mon \u003e CEPH_MAX_MON.\n\n[ idryomov: drop \"log output for unusual values of num_mon\" part ]","modified":"2026-08-21T03:30:37.880501998Z","published":"2026-08-10T11:59:21.200Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68155.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634"},{"type":"WEB","url":"https://git.kernel.org/stable/c/caf082ef8609a6ac26159ce115f55ab7d00231a3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3ccd4ecab09b22f507f49cb7ed9990c7158ceab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68155.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68155"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ba75bb98cfb93b62c54af25bf67ff90857264bbe"},{"fixed":"caf082ef8609a6ac26159ce115f55ab7d00231a3"},{"fixed":"e3ccd4ecab09b22f507f49cb7ed9990c7158ceab"},{"fixed":"0591a15815b498be628a937146e44487d599ba33"},{"fixed":"cd0d41bc569632eaaeccde9d2a6bc919ec00c407"},{"fixed":"e67e8b694872c9bc66996040f9de9242f6236ed9"},{"fixed":"3b249546f59c3d6d3592c10657f82bc3f1faa07c"},{"fixed":"40480eee361ed9676b3f844d532ac28b47251634"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-68155.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.34"},{"fixed":"5.15.216"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.183"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.148"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.101"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.42"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-68155.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}